This invention relates to carpet yarn useful for making textured cut-pile carpet and, more specifically, to such yarns made from nylon 66 copolymers.
The term "carpet yarn", as used herein, means a yarn consisting of two bulked continuous filament (BCF) singles yarns cabled together. Each singles yarn is individually bulked prior to being cabled together, usually, by jet bulking means.
The term "cut-pile" carpet, as used herein, means a carpet having an evenly sheared pile in the form of short lengths of carpet yarn (tufts). Each tuft projects upwardly and terminates as a cut end.
The term "nylon 66 copolymer", as used herein means a random fiber-forming polymer consisting of two or more different recurring units of which at least 50% by weight and no more than 97% by weight are of the formula: ##STR1##
The term "nylon 66", as used herein, does not include "nylon 66 copolymers".
Textured cut-pile carpet (hereinafter "textured" carpet) differs from conventional cut-pile carpet in that it is made from textured carpet yarn. One advantage that textured carpet has over conventional cut-pile carpet is that it shows reduced foot prints and reduced vacuum cleaning marks.
In commercial practice, nylon 66 carpet yarn, after being first textured by conventional methods and then heatset, is widely used for textured carpet applications. More specifically, the carpet yarn is fed through a stuffer box apparatus, with or without the use of steam, to compress the yarn. The yarn upon exiting the apparatus is permitted to fall in a wadded-up, crimped form onto the endless stainless steel, perforated belt of a Suberba.RTM. heatsetting machine. The belt passes slowly and continuously through a long chamber filled with saturated steam which is maintained at a temperature of about 138.degree. C. The yarn, after passing through the chamber, is cooled on the belt in its wadded-up, crimped form. The resulting heatset, textured carpet yarn is ready for tufting into textured carpet. (The term "heatset, textured" or "heatset, stuffer-box textured", when used herein with reference to carpet yarn, means that the carpet yarn is heatset after being textured.)
Unfortunately, the aesthetics and appearance retention characteristics of textured carpet made from heatset textured nylon 66 carpet yarn are disappointing. By "aesthetics" is meant the initial ("show room") appearance of the carpet. Factors which contribute to the aesthetics of textured carpet include carpet luster, texture level (tuft cut end to side contrast) and tuft cut end (endpoint) integrity. By "appearance retention" is meant the ability of the carpet to retain its initial appearance and resist matting when subjected to repeated foot traffic.